// $Id: farbtastic.js,v 1.4.2.1 2008/06/25 09:34:17 goba Exp $

// Farbtastic 1.2

jQuery.fn.farbtastic = function (callback) {

  $.farbtastic(this, callback);

  return this;

};

jQuery.farbtastic = function (container, callback) {

  var container = $(container).get(0);

  return container.farbtastic || (container.farbtastic = new jQuery._farbtastic(container, callback));

};

jQuery._farbtastic = function (container, callback) {

  // Store farbtastic object

  var fb = this;

  // Insert markup

  $(container).html('<div class="farbtastic"><div class="color"></div><div class="wheel"></div><div class="overlay"></div><div class="h-marker marker"></div><div class="sl-marker marker"></div></div>');

  var e = $('.farbtastic', container);

  fb.wheel = $('.wheel', container).get(0);

  // Dimensions

  fb.radius = 84;

  fb.square = 100;

  fb.width = 194;

  // Fix background PNGs in IE6

  if (navigator.appVersion.match(/MSIE [0-6]\./)) {

    $('*', e).each(function () {

      if (this.currentStyle.backgroundImage != 'none') {

        var image = this.currentStyle.backgroundImage;

        image = this.currentStyle.backgroundImage.substring(5, image.length - 2);

        $(this).css({

          'backgroundImage': 'none',

          'filter': "progid:DXImageTransform.Microsoft.AlphaImageLoader(enabled=true, sizingMethod=crop, src='" + image + "')"

        });

      }

    });

  }

  /**

   * Link to the given element(s) or callback.

   */

  fb.linkTo = function (callback) {

    // Unbind previous nodes

    if (typeof fb.callback == 'object') {

      $(fb.callback).unbind('keyup', fb.updateValue);

    }

    // Reset color

    fb.color = null;

    // Bind callback or elements

    if (typeof callback == 'function') {

      fb.callback = callback;

    }

    else if (typeof callback == 'object' || typeof callback == 'string') {

      fb.callback = $(callback);

      fb.callback.bind('keyup', fb.updateValue);

      if (fb.callback.get(0).value) {

        fb.setColor(fb.callback.get(0).value);

      }

    }

    return this;

  };

  fb.updateValue = function (event) {

    if (this.value && this.value != fb.color) {

      fb.setColor(this.value);

    }

  };

  /**

   * Change color with HTML syntax #123456

   */

  fb.setColor = function (color) {

    var unpack = fb.unpack(color);

    if (fb.color != color && unpack) {

      fb.color = color;

      fb.rgb = unpack;

      fb.hsl = fb.RGBToHSL(fb.rgb);

      fb.updateDisplay();

    }

    return this;

  };

  /**

   * Change color with HSL triplet [0..1, 0..1, 0..1]

   */

  fb.setHSL = function (hsl) {

    fb.hsl = hsl;

    fb.rgb = fb.HSLToRGB(hsl);

    fb.color = fb.pack(fb.rgb);

    fb.updateDisplay();

    return this;

  };

  /////////////////////////////////////////////////////

  /**

   * Retrieve the coordinates of the given event relative to the center

   * of the widget.

   */

  fb.widgetCoords = function (event) {

    var x, y;

    var el = event.target || event.srcElement;

    var reference = fb.wheel;

    // If the offset from the relative element is undefined calculate it.

    if ( typeof event.offsetX == 'undefined' && typeof event.offsetY == 'undefined' ) {

      var offset = $(event.target).offset(false);

      event.offsetX = event.pageX - offset.left;

      event.offsetY = event.pageY - offset.top;

    }

    // Use offset coordinates and find common offsetParent

    var pos = { x: event.offsetX, y: event.offsetY };

    // Send the coordinates upwards through the offsetParent chain.

    var e = el;

    while (e) {

      e.mouseX = pos.x;

      e.mouseY = pos.y;

      pos.x += e.offsetLeft;

      pos.y += e.offsetTop;

      e = e.offsetParent;

    }

    // Look for the coordinates starting from the wheel widget.

    var e = reference;

    var offset = { x: 0, y: 0 };

    while (e) {

      if (typeof e.mouseX != 'undefined') {

        x = e.mouseX - offset.x;

        y = e.mouseY - offset.y;

        break;

      }

      offset.x += e.offsetLeft;

      offset.y += e.offsetTop;

      e = e.offsetParent;

    }

    // Reset stored coordinates

    e = el;

    while (e) {

      e.mouseX = undefined;

      e.mouseY = undefined;

      e = e.offsetParent;

    }

    // Subtract distance to middle

    return { x: x - fb.width / 2, y: y - fb.width / 2 };

  };

  /**

   * Mousedown handler

   */

  fb.mousedown = function (event) {

    // Capture mouse

    if (!document.dragging) {

      $(document).bind('mousemove', fb.mousemove).bind('mouseup', fb.mouseup);

      document.dragging = true;

    }

    // Check which area is being dragged

    var pos = fb.widgetCoords(event);

    fb.circleDrag = Math.max(Math.abs(pos.x), Math.abs(pos.y)) * 2 > fb.square;

    // Process

    fb.mousemove(event);

    return false;

  };

  /**

   * Mousemove handler

   */

  fb.mousemove = function (event) {

    // Get coordinates relative to color picker center

    var pos = fb.widgetCoords(event);

    // Set new HSL parameters

    if (fb.circleDrag) {

      var hue = Math.atan2(pos.x, -pos.y) / 6.28;

      if (hue < 0) hue += 1;

      fb.setHSL([hue, fb.hsl[1], fb.hsl[2]]);

    }

    else {

      var sat = Math.max(0, Math.min(1, -(pos.x / fb.square) + .5));

      var lum = Math.max(0, Math.min(1, -(pos.y / fb.square) + .5));

      fb.setHSL([fb.hsl[0], sat, lum]);

    }

    return false;

  };

  /**

   * Mouseup handler

   */

  fb.mouseup = function () {

    // Uncapture mouse

    $(document).unbind('mousemove', fb.mousemove);

    $(document).unbind('mouseup', fb.mouseup);

    document.dragging = false;

  };

  /**

   * Update the markers and styles

   */

  fb.updateDisplay = function () {

    // Markers

    var angle = fb.hsl[0] * 6.28;

    $('.h-marker', e).css({

      left: Math.round(Math.sin(angle) * fb.radius + fb.width / 2) + 'px',

      top: Math.round(-Math.cos(angle) * fb.radius + fb.width / 2) + 'px'

    });

    $('.sl-marker', e).css({

      left: Math.round(fb.square * (.5 - fb.hsl[1]) + fb.width / 2) + 'px',

      top: Math.round(fb.square * (.5 - fb.hsl[2]) + fb.width / 2) + 'px'

    });

    // Saturation/Luminance gradient

    $('.color', e).css('backgroundColor', fb.pack(fb.HSLToRGB([fb.hsl[0], 1, 0.5])));

    // Linked elements or callback

    if (typeof fb.callback == 'object') {

      // Set background/foreground color

      $(fb.callback).css({

        backgroundColor: fb.color,

        color: fb.hsl[2] > 0.5 ? '#000' : '#fff'

      });

      // Change linked value

      $(fb.callback).each(function() {

        if (this.value && this.value != fb.color) {

          this.value = fb.color;

        }

      });

    }

    else if (typeof fb.callback == 'function') {

      fb.callback.call(fb, fb.color);

    }

  };

  /* Various color utility functions */

  fb.pack = function (rgb) {

    var r = Math.round(rgb[0] * 255);

    var g = Math.round(rgb[1] * 255);

    var b = Math.round(rgb[2] * 255);

    return '#' + (r < 16 ? '0' : '') + r.toString(16) +

           (g < 16 ? '0' : '') + g.toString(16) +

           (b < 16 ? '0' : '') + b.toString(16);

  };

  fb.unpack = function (color) {

    if (color.length == 7) {

      return [parseInt('0x' + color.substring(1, 3)) / 255,

        parseInt('0x' + color.substring(3, 5)) / 255,

        parseInt('0x' + color.substring(5, 7)) / 255];

    }

    else if (color.length == 4) {

      return [parseInt('0x' + color.substring(1, 2)) / 15,

        parseInt('0x' + color.substring(2, 3)) / 15,

        parseInt('0x' + color.substring(3, 4)) / 15];

    }

  };

  fb.HSLToRGB = function (hsl) {

    var m1, m2, r, g, b;

    var h = hsl[0], s = hsl[1], l = hsl[2];

    m2 = (l <= 0.5) ? l * (s + 1) : l + s - l*s;

    m1 = l * 2 - m2;

    return [this.hueToRGB(m1, m2, h+0.33333),

        this.hueToRGB(m1, m2, h),

        this.hueToRGB(m1, m2, h-0.33333)];

  };

  fb.hueToRGB = function (m1, m2, h) {

    h = (h < 0) ? h + 1 : ((h > 1) ? h - 1 : h);

    if (h * 6 < 1) return m1 + (m2 - m1) * h * 6;

    if (h * 2 < 1) return m2;

    if (h * 3 < 2) return m1 + (m2 - m1) * (0.66666 - h) * 6;

    return m1;

  };

  fb.RGBToHSL = function (rgb) {

    var min, max, delta, h, s, l;

    var r = rgb[0], g = rgb[1], b = rgb[2];

    min = Math.min(r, Math.min(g, b));

    max = Math.max(r, Math.max(g, b));

    delta = max - min;

    l = (min + max) / 2;

    s = 0;

    if (l > 0 && l < 1) {

      s = delta / (l < 0.5 ? (2 * l) : (2 - 2 * l));

    }

    h = 0;

    if (delta > 0) {

      if (max == r && max != g) h += (g - b) / delta;

      if (max == g && max != b) h += (2 + (b - r) / delta);

      if (max == b && max != r) h += (4 + (r - g) / delta);

      h /= 6;

    }

    return [h, s, l];

  };

  // Install mousedown handler (the others are set on the document on-demand)

  $('*', e).mousedown(fb.mousedown);

    // Init color

  fb.setColor('#000000');

  // Set linked elements/callback

  if (callback) {

    fb.linkTo(callback);

  }

};